Energy Efficient Excavator Hydraulic Systems With Digital Displacement® Pump-Motors and Digital Flow Distribution

Macpherson, Jill; Williamson, Christopher; Green, Matthew; Caldwell, Niall

doi:10.1115/fpmc2020-2770

Cited by 7 publications

(7 citation statements)

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“…Over and above, Pilot valves have more leakage than direct operated valves [143], respond slowly to pressure buildup [144], and are more complex in structure. And as might be expected, Pilot valves tend to have high power losses due to flow passes through bypass orifices [145,146].…”

Section: Generic Difficulties In Pilot Operated Valvesmentioning

confidence: 78%

A Review of Pilot-operated Hydraulic Valves – Development, Challenges, and a Comparative Study

Elsaed,

Linjama

2023

TJFP

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Hydraulic systems have been widely used due to their high power-to-weight ratio. Despite the growing instances of being superseded by the electromechanical counterparts at low power levels, the market was incapable of presenting alternatives for large-size applications. Additionally, in recent years, the demand for more significant heavy machinery (Mobile & Industrial) has increased, which led to the necessity of even higher flow and pressure Pilot-operated valves, despite the fact that these valves have several issues. One might think the alternative could be developing a hydraulic system that does not rely on Pilot-operated valves, but after decades of research, these systems could not get close to the performance of Pilot-operated Multistage valves. The paper presents a comprehensive study of the progress accomplished from the year 2016 to early 2022 in hydraulic Pilot-operated valves; they are widely employed among ordinary valves, proportional valves, and state-of-the-art digital hydraulics. Higher efficiency will be a primary factor in the success of the new designs. The academia presented several studies to improve the Pilot valves’ performance, but still, they are limited. There are no dramatic developments, and there are only a few upgrades.

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Section: Generic Difficulties In Pilot Operated Valvesmentioning

confidence: 78%

A Review of Pilot-operated Hydraulic Valves – Development, Challenges, and a Comparative Study

Elsaed,

Linjama

2023

TJFP

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“…Jill Macpherson et al carried out a backwardfacing simulation on an 18-ton excavator with the bus system architecture. The energy recycling capacity is raised by the digital displacement pump-motor, and it is confirmed that the simulated fuel saving is 53% to 58% [26]. M. Pellegri et al introduced the multiservice digital displacement pump to the excavator, which allows dynamic distribution of the pump displacement under different pressure levels.…”

Section: Introductionmentioning

confidence: 89%

Simulation Analysis of a Novel Digital Pump with Direct Recycling of Hydraulic Energy

Yue

Zuo

Liu

et al. 2023

Axioms

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There is a permanent and strong need for energy recovery to improve the efficiency of the hydraulic system in the field of the construction machinery. In addition, the digital pump will become powerful and versatile by employing different configurations and intelligent control of the flow distribution valves. Considering this case, we have proposed a novel digital pump in which every plunger is equipped with two flow distribution valves. By controlling these two valves, external hydraulic energy can be directly reused without other components. Based on the structure and working principle of the digital pump, the mathematical model is established and three working modes are detailed. To verify the feasibility and correctness of control methods, a performance simulation testing platform including a digital pump, load module, hydraulic energy to be recovered, and controller module was developed in AMESim R15 software. The pressure, flow rate, and torque simulations of the digital pump in three working modes were carried out. The simulation results have shown that the digital pump not only can be used as an ordinary pump but also has the function of recovery and immediate reutilization of another hydraulic energy. Meanwhile, the corresponding variable displacement control strategy is effective and the positive torque required to drive the digital pump can be reduced, which verified the energy-saving of this scheme. The ideas and contents in this paper can offer significant references for energy conservation technology of various engineering machineries and the intensive study of digital hydraulics.

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“…The possible displacement unit sizes are investigated based on the specification in Section 4.1, with offset in the static flow continuities. Considering the example with the VDN-PP topology depicted in Figure 9B with 0 ↔ 1 and 0 ↔ 3, the pressure dynamics appear as Equations ( 5) and ( 6): 7) and (8), bearing in mind that A 1 > A 2 , A 3 > A 4 , resulting in the displacement unit sizes in Equation ( 9):…”

Section: Possible Displacement Unit Sizes For Vdn-ppmentioning

confidence: 99%

“…The field of digital hydraulics has mainly evolved via two paths being digital flow control units and digital displacement units. In both cases, the switching valves and their control play a crucial role for system performance and efficiency [1][2][3][4][5]; however, the energy saving perspectives of digital hydraulics are indeed present and potential application areas broad [6][7][8][9][10][11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Electro-Hydraulic Variable-Speed Drive Networks—Idea, Perspectives, and Energy Saving Potentials

Schmidt

Hansen²

2022

Energies

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Electro-hydraulic differential cylinder drives with variable-speed displacement units as their central transmission element are subject to an increasing focus in both industry and academia. A main reason is the potential for substantial efficiency increases due to avoidance of throttling of the main flows. Research contributions have mainly been focusing on appropriate compensation of volume asymmetry and the development of standalone self-contained and compact solutions, with all necessary functions onboard. However, as many hydraulic actuator systems encompass multiple cylinders, such approaches may not be the most feasible ones with respect to efficiency or commercial feasibility. This article presents the idea of multi-cylinder drives, characterized by electrically and hydraulically interconnected variable-speed displacement units essentially allowing for completely avoiding throttle elements, while allowing for hydraulic and electric power sharing as well as the sharing of auxiliary functions and fluid reservoir. With drive topologies taking offset in communication theory, the concept of electro-hydraulic variable-speed drive networks is introduced. Three different drive networks are designed for an example application, including component sizing and controls in order to demonstrate their potentials. It is found that such drive networks may provide simple physical designs with few building blocks and increased energy efficiencies compared to standalone drives, while exhibiting excellent dynamic properties and control performance.

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Energy Efficient Excavator Hydraulic Systems With Digital Displacement® Pump-Motors and Digital Flow Distribution

Cited by 7 publications

References 0 publications

A Review of Pilot-operated Hydraulic Valves – Development, Challenges, and a Comparative Study

A Review of Pilot-operated Hydraulic Valves – Development, Challenges, and a Comparative Study

Simulation Analysis of a Novel Digital Pump with Direct Recycling of Hydraulic Energy

Electro-Hydraulic Variable-Speed Drive Networks—Idea, Perspectives, and Energy Saving Potentials

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